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Biology

Selected Works

2001

Articles 1 - 17 of 17

Full-Text Articles in Life Sciences

Growth And Metabolism Of Larval Zebrafish: Effects Of Swim Training, Brian P. Bagatto, B. Pelster, W. W. Burggren Dec 2001

Growth And Metabolism Of Larval Zebrafish: Effects Of Swim Training, Brian P. Bagatto, B. Pelster, W. W. Burggren

Brian P. Bagatto

Larval zebrafish (Danio rerio) of three different age classes ('yolk-sac' larvae, 96 h; 'swim-up' larvae, 9 days old; and 'free-swimming' larvae, 21 days old) were trained for 2, 6 and 11 days, respectively, to swim at 0 body lengths per second (BL s(-1)), 2 BL s(-1) and 5 BL s(-1). Survival was significantly diminished in larvae trained at 5 BL s(-1) compared to controls (0 BL s(-1)). Although training produced no significant differences in mass and length, the youngest larvae absorbed their yolk at a faster rate during training. Routine oxygen consumption (M(O2r)) and mass-specific routine oxygen consumption (MO(2r,m)) were …

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Blood-Squirting Variability In Horned Lizards (Phrynosoma), Wade Sherbrooke, George Middendorf, C. Guyer Oct 2001

Blood-Squirting Variability In Horned Lizards (Phrynosoma), Wade Sherbrooke, George Middendorf, C. Guyer

George Middendorf

Variability within the genus Phrynosoma in the occurrence of ocular-sinus blood-squirting, reportedly a defense used in canid encounters, is reviewed from the literature. Six species have been reported to squirt blood, and seven species remain unreported. Five of the latter species were tested in dog trials; one exhibited blood-squirting (Phrynosoma hernandesi), one exhibited precursor behaviors but failed to squirt blood (Phrynosoma ditmarsi), and three yielded negative results (Phrynosoma mcallii, Phrynosoma modestum, and Phrynosoma platyrhinos). Instances of blood-squirting in response to human encounters were collected and largely support the negative results for the three species P. mcallii, P. modestum, and P. …

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A Conserved Ubiquitin Ligase Of The Nuclear Envelope/Endoplasmic Reticulum That Functions In Both Er-Associated And Mat A2 Repressor Degradation, Rob Swanson Aug 2001

A Conserved Ubiquitin Ligase Of The Nuclear Envelope/Endoplasmic Reticulum That Functions In Both Er-Associated And Mat A2 Repressor Degradation, Rob Swanson

Rob Swanson

Substrate discrimination in the ubiquitin–proteasome system is believed to be dictated by specific combinations of ubiquitin–protein ligases (E3s) and ubiquitin-conjugating enzymes (E2s). Here we identify Doa10/Ssm4 as a yeast E3 that is embedded in the endoplasmic reticulum (ER)/nuclear envelope yet can target the soluble transcription factor Mat2. Doa10 contains an unusual RING finger, which has ubiquitin-ligase activity in vitro and is essential in vivo for degradation of 2 via its Deg1 degradation signal. Doa10 functions with two E2s, Ubc6 and Ubc7, to ubiquitinate Deg1-bearing substrates, and it is also required for the degradation of at least one ER membrane protein. …

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Characterization Of Partially Transesterified Poly(Β-Hydroxyalkanoate)S By Matrix-Assisted Laser Desorption/Ionization Time-Of-Flight Mass Spectrometry, Broderick Eribo May 2001

Characterization Of Partially Transesterified Poly(Β-Hydroxyalkanoate)S By Matrix-Assisted Laser Desorption/Ionization Time-Of-Flight Mass Spectrometry, Broderick Eribo

Broderick Eribo

Matrix-assisted laser desorption/ionization time-of-flight mass spectrometry (MALDI-TOFMS) was used for the characterization of a partially transesterified poly(beta-hydroxyalkanoate) (PHA), a polymer produced by the bacterial strain Alcaligenes eutrophus with saponified vegetable oils as the sole carbon sources. The transesterification was carried out separately under acidic and basic conditions to obtain PHA oligomers weighing <10 kDa. The intact oligomers were detected in their cationized forms, [M + Na]+ and [M + K]+, by MALDI-TOFMS. A composition analysis, using the MALDI-TOF spectra, indicated that the oligomers obtained via acid catalysis contained a methyl 3-hydroxybutyrate end group, and those obtained by base catalysis had …

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G Protein Regulation Of Ion Channels And Abscisic Acid Signaling In Arabidopsis Guard Cells, Hemayet Ullah, Xi-Qing Wang, Alan M. Jones, Sarah M. Assmann May 2001

G Protein Regulation Of Ion Channels And Abscisic Acid Signaling In Arabidopsis Guard Cells, Hemayet Ullah, Xi-Qing Wang, Alan M. Jones, Sarah M. Assmann

Hemayet Ullah

The phytohormone abscisic acid (ABA) promotes plant water conservation by decreasing the apertures of stomatal pores in the epidermis through which water loss occurs. We found that Arabidopsis thaliana plants harboring transferred DNA insertional mutations in the sole prototypical heterotrimeric GTP-binding (G) protein alpha subunit gene, GPA1, lack both ABA inhibition of guard cell inward K(+) channels and pH-independent ABA activation of anion channels. Stomatal opening in gpa1 plants is insensitive to inhibition by ABA, and the rate of water loss from gpa1 mutants is greater than that from wild-type plants. Manipulation of G protein status in guard cells may …

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Molecular Identification Of Smg-4, Required For Mrna Surveillance In C.Elegans, Rachel Aronoff, Renee Baran, Jonathan Hodgkin May 2001

Molecular Identification Of Smg-4, Required For Mrna Surveillance In C.Elegans, Rachel Aronoff, Renee Baran, Jonathan Hodgkin

Renee Baran

Premature termination codons trigger a process in eukaryotes known as nonsense mediated decay or mRNA surveillance, resulting in the rapid decay of the aberrant transcript. Studies in C.elegans have shown this system is mediated by seven smg genes and can prevent the accumulation of toxic, truncated peptides. Here we report the cloning of smg-4 by physical mapping and functional rescue assays. The minimal rescuing activity is found within a genomic operon, encoding a novel protein. The final exon of the gene is alternatively spliced for expression of two different isoforms. Although no known genes were found to exhibit significant homology …

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Abp1 Is Required For Organized Cell Elongation And Division In Arabidopsis Embryogenesis, Hemayet Ullah Mar 2001

Abp1 Is Required For Organized Cell Elongation And Division In Arabidopsis Embryogenesis, Hemayet Ullah

Hemayet Ullah

To directly address the function of a putative auxin receptor designated ABP1, a reverse genetic approach was taken to identify and characterize ABP1 mutant alleles in Arabidopsis. A homozygous null mutation in ABP1 confers embryo lethality. Null mutant embryos develop normally until the early stages of the globular embryo but are unable to make the transition to a bilaterally symmetrical structure because cells fail to elongate. Cell division was also aberrant both in the suspensor and embryo proper. Antisense suppression of ABP1 in tobacco cells causes slow proliferation and eliminates auxin-induced cell elongation and reduces cell division. The complete lack …

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On The Status Of The Serranid Fish Genus Epinephelus: Evidence For Paraphyly Based Upon 16s Rdna Sequence, Matthew T. Craig, Daniel Pondella Ii, Jens P.C Franckb, John C. Hafner Mar 2001

On The Status Of The Serranid Fish Genus Epinephelus: Evidence For Paraphyly Based Upon 16s Rdna Sequence, Matthew T. Craig, Daniel Pondella Ii, Jens P.C Franckb, John C. Hafner

Daniel Pondella

Historically, attempts to elucidate evolutionary relationships among members of the genus Epinephelus (Teleostei: Serranidae), commonly known as groupers, have been hindered by the overwhelming number of species (98, sensu stricto), a pan global distribution, and the lack of morphological specializations traditionally used in ichthyological classification. To date, no comprehensive phylogenetic study, morphological or molecular, to evaluate the monophyly of this genus has been presented. In this study, previous hypotheses regarding the relationships among the American grouper species and the allied genera were evaluated by examination of mitochondrial DNA sequences of the 16S ribosomal DNA region. A 590-bp region of the …

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Behavioural Assessment Of Visual Acuity In Bumblebees (Bombus Impatiens), Robert Gegear, Todd Macuda, Terence Laverty, Brian Timney Jan 2001

Behavioural Assessment Of Visual Acuity In Bumblebees (Bombus Impatiens), Robert Gegear, Todd Macuda, Terence Laverty, Brian Timney

Robert J. Gegear

measure resolution acuity in bumblebees (Bombus impatiens). Bees were required to discriminate between horizontal and vertical gratings in a Y-maze apparatus. The gratings had a mean luminance of 9 cd m−2 and a Michelson contrast of 84 %. For different bees, either the horizontal or vertical grating was rewarded. Rewarded gratings were associated with a sucrose and water solution (30 % sucrose by volume) and unrewarded gratings with plain water. Acuity estimates were established at several different viewing distances over several sessions using a method of constant stimuli. Visual acuity functions were generated from the performance data, and acuity thresholds …

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The Pattern, Rate, And Range Of Within-Patch Movement Of A Stem-Galling Fly, Warren Abrahamson, J.T. Cronin, K. Hyland Dec 2000

The Pattern, Rate, And Range Of Within-Patch Movement Of A Stem-Galling Fly, Warren Abrahamson, J.T. Cronin, K. Hyland

Warren G. Abrahamson, II

No abstract provided.

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Temporal Variation In Herbivore Host-Plant Preference And Offspring Performance: Constraints On Host-Plant Adaptation, Warren Abrahamson, J.T. Cronin, T.P. Craig Dec 2000

Temporal Variation In Herbivore Host-Plant Preference And Offspring Performance: Constraints On Host-Plant Adaptation, Warren Abrahamson, J.T. Cronin, T.P. Craig

Warren G. Abrahamson, II

No abstract provided.

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Gall Flies, Inquilines, And Goldenrods: A Model For Host-Race Formation And Sympatric Speciation, Warren Abrahamson, M.D. Eubanks, C.P. Blair, A.V. Whipple Dec 2000

Gall Flies, Inquilines, And Goldenrods: A Model For Host-Race Formation And Sympatric Speciation, Warren Abrahamson, M.D. Eubanks, C.P. Blair, A.V. Whipple

Warren G. Abrahamson, II

No abstract provided.

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Do Parasitoids Diversify In Response To Host-Plant Shifts By Herbivorous Insects?, Warren Abrahamson, J.T. Cronin Dec 2000

Do Parasitoids Diversify In Response To Host-Plant Shifts By Herbivorous Insects?, Warren Abrahamson, J.T. Cronin

Warren G. Abrahamson, II

No abstract provided.

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Hydraulic Conductance And Mercury-Sensitive Water Transport For Roots Of Opuntia Acanthocarpa In Relation To Soil Drying And Rewetting, P. Martre, Gretchen North, P. Nobel Dec 2000

Hydraulic Conductance And Mercury-Sensitive Water Transport For Roots Of Opuntia Acanthocarpa In Relation To Soil Drying And Rewetting, P. Martre, Gretchen North, P. Nobel

Gretchen North

Drought-induced changes in root hydraulic conductance (L P) and mercury-sensitive water transport were examined for distal (immature) and mid-root (mature) regions ofOpuntia acanthocarpa. During 45 d of soil drying,L P decreased by about 67% for distal and mid-root regions. After 8 d in rewetted soil,L P recovered to 60% of its initial value for both regions. Axial xylem hydraulic conductivity was only a minor limiter of L P. Under wet conditions, HgCl2 (50 μM), which is known to block membrane water-transport channels (aquaporins), decreasedL P and the radial hydraulic conductance for the stele (L R, S) of the distal root …

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Demographic Parameters Of Golden Spotted Rock Bass Paralabrax Auroguttatus From The Northern Gulf Of California, Daniel Pondella Ii, Larry G. Allen, Jorge A. Rosales Casian, Tim E. Hovey Dec 2000

Demographic Parameters Of Golden Spotted Rock Bass Paralabrax Auroguttatus From The Northern Gulf Of California, Daniel Pondella Ii, Larry G. Allen, Jorge A. Rosales Casian, Tim E. Hovey

Daniel Pondella

The sex ratios, growth, and mortality of the golden spotted rock bass Paralabrax auroguttatus (Serranidae) were determined for populations from Islas Encantadas and Bahía de los Angeles in the Gulf of California. Specimens ranged from 137 to 479 mm standard length and from 135 to 3,100 g. Sagittal otoliths were used to determine age. A von Bertalanffy model of growth for both populations combined was estimated as Lt = 474.4·(1 − e −0.115( t + 2.093)), where Lt is fish length at age t. This model is comparable to those for other rock basses. The relationship between length and weight …

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Body Size And Survivorship In Overwintering Populations Of Porcellio Laevis (Isopoda: Oniscidea), Scott Kight Dec 2000

Body Size And Survivorship In Overwintering Populations Of Porcellio Laevis (Isopoda: Oniscidea), Scott Kight

Scott Kight

Because female Porcellio laevis (Isopoda: Oniscidea) carry eggs and young manca in a ventral marsupium, fecundity and body size are positively correlated. We examined female body size in November and February, a period in which breeding does not occur and changes in body size are unlikely to be attributed to growth. Our results from two consecutive years revealed several general patterns. First, the sex-ratio of individuals collected with baited traps was extremely female biased. Second, body size was significantly larger (as indicated by length of antennae and appendages) in samples collected during November than in those collected during February. Third, …

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Taxonomy And Biology Of A New Oecophoridae (Lepidoptera) From Central Chile, T. Heath Ogden Dec 2000

Taxonomy And Biology Of A New Oecophoridae (Lepidoptera) From Central Chile, T. Heath Ogden

T. Heath Ogden

The adult, larva, and pupa of Afdera jimenae Ogden & Parra sp. nov. are described and illustrated. Larvae live in leaf litter throughout all instars and are generalists feeding upon the fallen leaves of a number of different plant species of sclerophyllous forests. Comments on morphological details and bionomics of this species are given. This is the second species of Afdera know for Chile.

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